public void BasketTotalAmount_GivenBasket_BaksetTotalAmountShouldBe10() { //Arrange var expected = 10; IPriceEngine priceEngine = new PriceEngine(); ICheckout checkout = new Checkout(priceEngine); var basket = new Basket(); var itemA = new BasketItem("A"); basket.Add(itemA); //Act var total = checkout.BasketTotalAmount(basket.basketItems); //Assert Assert.That(total, Is.EqualTo(expected)); }